In the USA, about 36 million adults suffer from hearing loss and three out of every 1,000 children are born deaf or hard-of-hearing. When conventional hearing aids provide no appreciable benefit, implantable electronic devices using electrode arrays inside the cochlea are a viable solution. With these cochlear implants, the profoundly deaf achieve reasonable word recognition in quiet environments. However, current technology has limited capabilities and little room for innovation due to the use of hand assembly for the implanted electrode arrays. This tedious manufacturing method is very costly, extremely labor-intensive, and inadequate in implementing new technologies for improving speech recognition and music appreciation. A superior alternative to hand assembly is MEMS fabrication, which is a fully automated, low cost, and high yield manufacturing process that is capable of implementing a variety of innovations, including smaller array size for residual hearing preservation, drug delivery channels for inner ear health and cell regeneration, and strain gauges for improved performance during surgical insertion. MEMS fabrication is a very promising alternative to hand-assembly, but until now no MEMS-based electrode array has achieved all requirements for commercialization: (1) substrates composed of proven, long-term implantable materials; (2) compatibility with standard surgical insertion techniques; and (3) robust substrate and stimulation sites capable of withstanding long-term use. Our novel MEMS manufacturing process meets all these requirements and will be the first to utilize robust medical-grade materials, silicone and electroplated platinum. Surgical compatibility is accomplished through a patented array-on-channel process providing a guide for a stylet-wire in the advanced- off-stylet surgical insertion method and setting the array stiffness for direct forceps placement. We will use industry standard test methods critical for FDA approval to demonstrate the excellent capabilities of our manufacturing approach by evaluating electrical characteristics, mechanical durability, and biocompatibility of the fabricated cochlear electrode arrays. The outcome is a MEMS-fabricated electrode array that complies with important requirements for clinical use and commercialization.